Photodynamic therapy (PDT) is a clinically approved and rapidly evolving treatment regimen for disease including cancer, cardiovascular disease, dermatological diseases and ophthalmic disease. PDT traditionally involves administration of a photosensitizer that preferentially accumulates within a target tissue site. Following illumination of the tissue site with light of an appropriate wavelength, in the presence of molecular oxygen, reactive oxygen species, such as singlet oxygen, free radicals and peroxides are produced which, in turn, damage cellular structures containing the photo-sensitizer. The effects are localized to the vicinity of the target tissue and within a few millimeters of the light source, which minimizes systemic and normal tissue toxicity.
Both disease treatment and detection depend on the selective delivery of appropriate agents to the affected tissue site. Current photodynamic therapeutic agents lack effective tissue localization. There remains a need for compositions and methods to detect and treat target cells and/or tissues in a non-invasive manner. The present invention satisfies these and other needs.